Motor fuels and preparation thereof



Patented Jan. 20, 1945 Mo'roa FUELS AND PREPARATION 'rnnaaor Walter A. Herbst, Union, N. 1., assignor Standard Development Company, a corporation of Delaware No Drawing. Application October 30, 1943, Serial No. 508,371

4 Claims. (CL 44-74) This invention relates to novel motor fuels, particularly high anti-knock aviation engine fuels. and to methods of preparing same.

It is known that aromatic amines such as toluidine, xylidines, etc. are especially good anti-knock agents for motor fuels, even when used in relatively small amounts in the range of /2%, 1% or 2%, but considerable difficulty has been experienced from the point of View that motor fuels to which such aromatic amines have been added tend to go off color, 1. e., to darken during storage, much more than similar fuels without such aromatic amines. Some stabilizers have been found which tend to prevent or to reduce the discoloration of the aromatic amines per so during storage,

but even when such stabilizers are used in fuels containing the aromatic amines substantial discoloration dimculties have still persisted.

The primary object of the present invention is to overcome these diificulties and to prepare high anti-knock motor fuels containing aromatic also containing a color stabilizer for said aromatic 2 without partially etherized polyhydric phenols),

xylenols, tertiary butyl para cresoi, hydroqulnone, R v

tertiary butyl ether of ortho tertiary butyl para cresoi, or other tertiary alkyl ethers of alkyl phenols, diamyl phenol, petroleum phenols or alkylated products thereof, etc.

The amount of such gum inhibitor need only be a very small amount such as about 0.1 to 1.0 lbs/1000 gallons of fuel, the exact amount to be used depending primarily upon the gum forming tendencies of the hydrocarbon fuel base stock a used and the intended storage conditions of time,

temperature, etc. I

The hydrocarbon fuel base stock may consist of any suitable gasoline base stock such as straight run or cracked petroleum distillates from amines, is that certain other materials which had been added to the motor fuel for preventing gum formation in the hydrocarbon fuel base stock, had reacted in some deleterious manner with either the aromatic amines. per se or with the color stabilizer, or in some unknown manner had not only failed to let the color stabilizer perform its normal function in stabilizing the aromatic amine against discoloration, but in some instances actually accelerated or aggravated the discoloration of the aromatic amine. investigation it has been found that the gum inhibitors which cause this deleterious action are those which contain amino groups such as normal butyl para amino phenol, isobutyl para amino phenol, mono benzyl para amino phenol, etc. On the other hand, it has been found that alkylated hydroxy aromatic compounds free from amino groups may be used satisfactorily in motor fuels After substantial paraflinic, naphthenic, mixed base, or other suit- ,able crude petroleums, products made by special processes such as polymerization, 'alkylation,

lsomerization, hydrogenation, etc; or mixtures of agents may include, for example, one or more of the various alcohols such as methanol, ethanol, isopropyl alcohol, tertiary butyl alcohol, etc.; or various anti-knock ethers such as (ii-isopropyl ether, ethyl isopropyl ether, methyl tertiary butyl ether, etc.; or ketones such as acetone, methyl isopropyl ketone, etc.

' Although broadly the invention applies to any of the above types of base stocks suitable for motor fuel, regardless of octane number, the invention is particularly applicable to base stocks having an A. S. T. M. octane number of at least '70.

The aromatic amine which is to be used according to this invention may be any one which is sufliciently soluble in the gasoline base stock and which has a suitable boiling point or boiling range and is otherwise suitable as a potent anti-Knock agent. Although the invention is intended to apply broadly to any such aromatic amines, it is believed particularly applicable to alkaryl amines, especially those having from 1 to 3 carbon atoms such as one or more of the xylidines which have the chemical formula: (CH3) 2CsHaNHz; either the pure separate isomer may be used or mixtures thereof. Qther alkaryl amines which may be aasaeao used include the toluidines, ortho. meta or para. or mixtures thereof, the several ethyl anilines, cumidine (which is isopropyl aniline), etc. Although it is preferred to use such allraryl amines, other aromatic amines may be used'such as aniline, the various naphthylamines such as isopropyl .or tertiary butyl naphthylamine, and the-various derivatives of aniline in which either or both of the hydrogens of the amino group are substituted by hydrocarbons, i. e., either alkyl or aryl groups, e. g., N-monomethyl aniline, N-dimethyl aniline, N-monoethyl aniline, etc. Thus the aromatic amines may be primary, secondary.

I or tertiary amines.

The amount of such aromatic amines to be used will depend primarily upon the desired increase in octane number, but normally will range from about 0.5 to 5.0%, generally about 1 or 2% being found satisfactory.

The susbtance to be added for the primary purpose of stabilizing the aromatic amine against discoloration'during storage may be selected from a fairly large group of materials such as the various organicsulfur compounds, particularly of the aryl mercaptan type, such as p-thiocresol, or other alkyl aromatic mercaptans, preferably having one to six alkyl carbon atoms, or heterccyclic organic compounds containing sulfur, such as thiophene or carbon disulfide, or even elemental sulfur. These various materials may be classed broadly as sulfur-containing stabilizers. The amount of such stabilizer to be used may range from about .0005% to .1% or preferably about .002 to 05% based on the total volume of motor fuel.

The invention also contemplates the use of metallo organic anti-knock agents, especially of the tetraethyl lead (T. E. L.) type, particularly in preparing high octane aviation motor fuels, and the amount of such addition agent may range from about 0.5 to 4 or even 6 cc. or more per gallon of. motor fuel. In place of tetraethyl lead one may use other lead alkyl anti-knock agents 'such as tetramethyl lead, dimethyl diethyl lead.

etc.

For the sakeof illustration, the following specific examples are given:

Example I A high octane aviation motor fuel was prepared by blending together the following mate rial:

1 lb./5000 gals. tricresol,

1 1b./5000 gals. of carbon disulflde.

Example II Same as Example I, except for the last two items which are as follows:

0.5 lb./5000 gals. tricresol, 0.5 lb./5000 gals. carbon bisulfide.

Example HE 0.5 lb./ 5000 gals. tricresol, 0.5 1b./5000 gals. p-thiocresol.

Example IV Same as Example 1, except for the last two items which are as follows:

i lb./5000 gals. alkylated cresols, l lb./5000 gals. carbon disulfide.

It is not intended that this invention be limited to the particular materials which have been given merely for the sake of illustration, nor necessarily by any theory suggested as to the mechanism of the operation of the invention, but only by the appended claims in which it is intended to claim all novelty inherent in the invention as well as all modifications coming within the scope and spirit of the invention.

I claim:

1. A motor fuel composition comprising gasoline hydrocarbons, a knock reducing amount of aromatic amine, a gum inhibiting amount of allrylated hydroxy aromatic oxidation inhibitor free from any amino substitucnts and a sufficient amount of carbon disulflde to stabilize the aromatic amine present in said fuel against discoloration during storage.

2. A motor fuel according to claim 1 containing at least 50% by volume of hydrocarbon base stock and about 0.5 to 5.0% of alkaryl amine antiknoclr agent containing 1 to 3 alkyl carbon atoms.

3. A motor fuel according to claim 1 in which the carbon disulflde is present in an amount less than 0.1

4. A motor fuel composed essentially of the following ingredients: about 9099% of hydrocarbon fuel base stock of the gasoline boiling range and having an octane number of at least 0.5 to 2% of xylidine; about 0.1 to 1.01b./1000 gallons of alkylated hydroxy aromatic gum inhibitor free of any amino substitucnt; about- .0005% to .1% of carbonrdisulflde. and 0.5 to 6.0 cc. of tetraethyl lead per gallon of fuel.

WALTER A. HERBST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,184,727 Cosmo May 30, 1916 1,571,862 Midgley Feb. 2, 1926 2,410,847 Walters Nov. 12, 1946 Re. 19,512 Bjerregaard Apr. 2, 1935 FOREIGN PATENTS Number Country Date 432,480 Great Britain' July 22, 1935 OTHER REFERENCES Bulich; Chemical Abstracts, vol. 28, page 1335 (1934). 

